Your DH needs to stop. And take a chill pill . Literally. I felt stressed and panic just reading your post. His input is not helpful in any way and has probably hindered the whole situation.
I feel so sorry for your DS "A level results disappointing to say the least.."
He's two marks off getting the grade for his apprenticeship. Instead of berating him, catastrophizing, stress farting etc at him in such a resentful way..everyone needs to calm down. Stop a moment and think. If you are exhausted by it, how do you think your son feels?
Two marks off!!!
Why aren't you contacting the careers person at his school and the applications office at his apprenticship /college putting forward if you can, his positive points. ask if they have any advice.
There are many people who apply and either don't get it or take a different offer... so there is always some wiggle room. I know loads of kids who have got through in this way.. That's what Clearing is for, but I''ve also succcessfully rung an admissions officer when my DS was just one grade short.
"I've realised that I've been babying DS in order to calm DH's anxiety and I just can't do it any more. It hasn't worked." So none of this is even about your son but all about placating your hyped up DH. Why?
The poor lad has just missed his course place by only 2 marks,
he's stuck up in his room listening to the two you of creating and catastrophizing about how he's messed up
When he does send off an application on his own, to address the babying accusations, your DH flips his lid and "bets" DS has made loads of mistakes.
Sorry OP but that sounds abusive. DH bets, but he doesn't know. Did he even read it? No wonder your Son was literally scared to show it to either of you.
That sounds confidence sapping to me and there's zero motivation to work when you live with constant criticism.
The best thing you can do is help (without criticising) your DS with contacting the applications officer. And get your son to have an appointment with whoever advises him at school. As your DH has proven so utterly useless and unhelpful to the situation, I would keep it between you and your son until he gets a solution he is happy with.
I do sympathise with your exhaustion, but I tnink it is your DH that is causing it rather than your DS.
Your DS is at a pivotal point in his life. He's moved out of the school stage and is in the preparing to fly the nest stage and you will miss him when that happens. So you won't have the opportunity to support him in this way for much longer.
A change of approach is needed. He's becoming an adult. Instead of asking why he hasn't done this or that... try asking how he feels about things, really talk and really listen.
What he needs now is positive support and encouragement, the carrot and not the stick, because the world of work is bloody hard at the moment and you need to be telling him that yes he can do it, not blaming the past.
He's already trying to do his own applications, so encourage him. He needs to know that you can ask you to look over something without a huge outcry. You wouldn't do that to a colleague at work would you?
Don't allow DH to hit the roof every time there is a set back. That is going to have a very negative effect on your son. The A levels are a hurdle and he can find a different route or a way around it as long as he has the encouragement to keep looking. And he may have to apply for endless jobs at the moment and get endless rejections... it's a fact of life... but as parents you have to accept that and encourage him that it's worth it to keep applying because he has the ability and will get there eventually.